A photoelectric conversion device, having a horizontally long rectangular shape, includes a pixel block including pixels; signal processing blocks, arranged along a transverse direction of the photoelectric conversion device, for processing a pixel signal; a power source voltage supply block for supplying a power source voltage. The pixel includes a photoelectric conversion element for performing a photoelectric conversion, and a charge/voltage conversion unit, including a first amplifier, for converting the converted charge into a voltage. In the pixel block, columns are arranged in a longitudinal direction. Each column is set as a unit of signal processing including a predetermined number of pixels. Vertical power feeding wirings for feeding the power source voltage to the columns of the pixel block, from the transverse direction, are arranged. Horizontal power feeding wirings for feeding the power source voltage to the pixel block and the signal processing blocks, from the longitudinal direction, are arranged.